On Tuesday, Virgin Galactic, the company he founded more than a decade ago with the goal of flying tourists to the edge of space and back, performed another test flight over the Mojave Desert in California, US.

SpaceShipTwo "Unity," a winged space plane, went supersonic for the second time, firing its engine for just 31 seconds. But that was enough to power the vehicle to an altitude of nearly 22 miles (35km) and a maximum speed of almost Mach 2, or twice the speed of sound.

In an interview after the flight, Branson said, "It was as good as it gets today." The pilots, he said, "came back with massive beams on their faces. It's a big, big step today."

The company plans to have another test flight in about six weeks or so, he said, and then it could attempt to reach the edge of space on the next flight - but that would depend on how the vehicle performs in the test flights.

Virgin Galactic, which charges US$250,000 ($362,940) a ticket, has some 700 people signed up to fly, and Branson has said he would be among the first to go. To prepare for his flight, which he has said could come this year, the 67-year-old said he's been cycling, playing tennis in the morning and evening, and spending time in a centrifuge to get his body used to the additional gravitational forces passengers would experience on SpaceShipTwo.

Blue Origin, the space company owned by Jeff Bezos, is also aiming to fly its first test flights with people by the end of this year. (Bezos owns The Washington Post.)

Branson said he expected that the companies would both "have a person in space roundabout the same time". But he said they "are not in a race to get to space.... All that matters in the end is that everybody is safe and well."

Yes, getting closer. Altitude 35 km. The plan is to get above 100 km in order to be defined as space flight. So they have a long way to go. If you are a ticket holder you can relax for a very long time yet.

On a blindingly bright January afternoon in 2010, I went to my bank to get a cashier's check for $20,000. It was my birthday, and I was buying myself the present I'd been waiting for my entire life: a trip to space.

This fat chunk of cash would become a 10 percent downpayment for a ticket aboard Virgin Galactic, billionaire Richard Branson's bold plan to hurl ordinary humans into space. To do this, Branson plans to use rocket planes that can carry space tourists 62 miles up and travel at three times the speed of sound. Ninety days before my trip, I'd need to pay the remaining $180,000. That's $200,000 for a five-minute sojourn beyond Earth's stratosphere.

In July 2008, Richard Branson predicted the maiden space voyage would take place within 18 months.[2] In October 2009, Virgin Galactic announced that initial flights would take place from Spaceport America "within two years."[12] Later that year, Scaled Composite announced that White Knight Two's first SpaceShipTwo captive flights would be in early 2010.[13] Both aircraft did fly together in March 2010.[14] The credibility of the earlier promises of launch dates by Virgin Galactic were brought into question in October 2014 by its chief executive, George Whitesides, when he told The Guardian: “We’ve changed dramatically as a company. When I joined in 2010 we were mostly a marketing organisation. Right now we can design, build, test and fly a rocket motor all by ourselves and all in Mojave, which I don’t think is done anywhere else on the planet”

The two companies leading the pack in the pursuit of space tourism say they are just months away from their first out-of-this-world passenger flights -- though neither has set a firm date.

Virgin Galactic, founded by British billionaire Richard Branson, and Blue Origin, by Amazon creator Jeff Bezos, are racing to be the first to finish their tests -- with both companies using radically different technology.

Moments of weightlessness

Neither Virgin nor Blue Origin's passengers will find themselves orbiting the Earth: instead, their weightless experience will last just minutes. It's an offering far different from the first space tourists, who paid tens of millions of dollars to travel to the International Space Station (ISS) in the 2000s.

Having paid for a much cheaper ticket -- costing $250,000 with Virgin, as yet unknown with Blue Origin -- the new round of space tourists will be propelled dozens of miles into the atmosphere, before coming back down to Earth. By comparison, the ISS is in orbit 250 miles (400 kilometers) from our planet.

The goal is to approach or pass through the imaginary line marking where space begins -- either the Karman line, at 100 kilometers or 62 miles, or the 50-mile boundary recognized by the US Air Force.

At this altitude, the sky looks dark and the curvature of the earth can be seen clearly.

Virgin Galactic

With Virgin Galactic, six passengers and two pilots are boarded onto SpaceShipTwo VSS Unity, which resembles a private jet.

The VSS Unity will be attached to a carrier spacecraft -- the WhiteKnightTwo -- from which it will then detach at around 49,000 feet (15,000 metres.) Once released, the spaceship will fire up its rocket, and head for the sky.

Then, the passengers will float in zero-gravity for several minutes, before coming back to Earth.

The descent is slowed down by a "feathering" system that sees the spacecraft's tail pivot, as if arching, before returning to normal and gliding to land at Virgin's "spaceport" in the New Mexico desert.

In total, the mission lasts between 90 minutes and two hours. During a May 29 test in California's Mojave desert, the spaceship reached an altitude of 21 miles, heading for space.

In October 2014, the Virgin spaceship broke down in flight due to a piloting error, killing one of two pilots on board. The tests later resumed with a new craft.

The company has now also reached a deal to open a second "spaceport" at Italy's Tarente-Grottaglie airport, in the south of the country.

Branson in May told BBC Radio 4 that he hoped to himself be one of the first passengers in the next 12 months. About 650 people make up the rest of the waiting list, Virgin told AFP.

Blue Origin

Blue Origin, meanwhile, has developed a system closer to the traditional rocket: the New Shepard.

On this journey, six passengers take their place in a "capsule" fixed to the top of a 60-foot-long rocket. After launching, it detaches and continues its trajectory several miles toward the sky. During an April 29 test, the capsule made it 66 miles.

After a few minutes of weightlessness, during which passengers can take in the view through large windows, the capsule gradually falls back to earth with three large parachutes and retrorockets used to slow the spacecraft.

From take-off to landing, the flight took 10 minutes during the latest test.

Until now, tests have only been carried out using dummies at Blue Origin's West Texas site.

Company officials were recently quoted as saying the first tests with Blue Origin astronauts would take place "at the end of this year," with tickets for the public expected to go on sale in 2019.

But in comments to AFP Friday, the company struck a more cautious note.

"We have not set ticket pricing and have had no serious discussions inside of Blue on the topic," the firm said. "We have a flight test schedule and schedules of those types always have uncertainties and contingencies. Anyone predicting dates is guessing."

What's next?

SpaceX and Boeing are developing their own capsules to transport NASA astronauts, most likely in 2020, after delays -- a significant investment that the companies will likely make up for by offering private passenger flights.

"If you're looking to go to space, you'll have quadruple the menu of options that you ever had before," Phil Larson, assistant dean at the University of Colorado, Boulder's College of Engineering and Applied Science, told AFP.

Longer term, the Russian firm that manufactures Soyuz rockets is studying the possibility of taking tourists back to the ISS. And a US start-up called Orion Span announced earlier this year it hopes to place a luxury space hotel into orbit within a few years -- but the project is still in its early stages.

Roger, thanks for that. I did see another report regarding the recent test which suggested that there are still vibration issues with the craft caused by the rocket motor. Also payload appears to be an issue together whether the craft is actually able to reach the design height of 100km. I liked this quote from Branson in the Guardian article:-

"Today we have shown that Virgin Galactic really can open space to change the world for good,” he said. I wonder how the world will change?